Vintage Allegro razor blade sharpener, likely from the mid-20th century

This particular model is a Swiss-made Allegro sharpener, as indicated by the "Made in Switzerland" inscription. It features a two-sided mechanism, typically with a sharpening stone on one side and a honing leather on the other, designed to sharpen double-edged blades. These sharpeners were popular for extending the life of razor blades during a time when disposable blades were less common. Vintage Allegro sharpeners are often sought after by collectors and enthusiasts of traditional shaving tools.